Fortunately the Earth’s magnetosphere deflects most of these away from us. But the field comes back to Earth at the poles and these high energy charged particles come rushing down into the atmosphere (in some cases accelerated by the Earth’s magnetic field).
These particles “excite” the atoms in the air by giving the atoms electrons more energy, which then get rid of the energy again as light. Blue or Red for nitrogen (70% of the air) and Red and Green for the oxygen.
At high altitude oxygen red dominates, then oxygen green and nitrogen blue/red, then finally nitrogen blue/red when collisions prevent oxygen from emitting anything. Green is the most common of all auroras. Behind it is pink, a mixture of light green and red, followed by pure red, yellow (a mixture of red and green), and lastly pure blue.
Just like iron filings line up along a magnetic field, so do the charged particles. We get sheets of air glowing when hit by the particles following the Earth’s field lines, drifting and swirling around. We call them Aurora. Aurora Borealis (a.k.a. The Northern Lights) and Aurora Australis (The Southern Lights).
Here is a BBC Stargazing Live video explaining Aurora – it’s aimed at Primary kids so it’s kept nice and simple.
Below is a slide show of Aurora photos taken during January 2012.
Sources: Wikipedia, BBC News, BBC Stargazing Live, Various Newspaper websites.
Tonight’s Bang Goes the Theory showed a brilliant experiment where people (MP’s in this case) judge risk by the words used to describe it. It can be easy to sway people to be for or against something by the wording. (That is one of the things I researched and discussed for my MSc in Science course…)
You can catch the episode on iPlayer for the next month.
As part of the episode Bang, along with Lab UK launched The Big Risk Test for you the GB public to take part in.
Sources: BBC Bang Goes The Theory, BBC YouTube
Unless you’ve been hiding under your pillow for the last few days you must have heard of the magnitude
8.9 9 Earthquake that happened under the ocean near Japan, causing a massive Tsunami that flooded much of the coast.
Here you can see footage of the
And here you can see pictures of the damage by sliding the bar to see the before and after pictures.
You can see from this diagram why the tsunami killed so many people – the earthquake was so close to the shore there was only minutes to warn and evaquate people.
The full details of the earthquake can be found here on the usgs.com website
The first episode of the new series of BBC’s Bang Goes the Theory was dedicated to the science behind the Japan earthquake and tsunami. You can watch it on iPlayer here.
Here is a clip from the episode showing how earthquake build up so much energy and how tsunami are formed when the seabed shifts suddenly.
Japan has a good record of designing buildings that can survive earthquakes, as can been seen in the video. Wooden buildings are generally good because they can flex without breaking. But a tsunami is a different proposition – with a large mass of water flowing through them few buildings can survive.
During the earthquake Japans nuclear reactors were shut down. Control rods moved in to stop the reactions, but nuclear reactors get very hot and it takes days and weeks to cool them down. Unfortunately it is the cooling of the reactors that has been the problem. Water pumps have been damaged, so the coolant inside the reactors has been boiling, needing releases of pressure that have taken small amounts of radioactive material with them. Some of these pressure releases exploded – the coolant water having split into hydrogen and oxygen. If the coolant falls below the level of the fuel rods, the fuel rods can over heat and start to melt – this is called a melt down.
As long as the main case of the reactor is not damaged then the bulk of the radioactive material remains safe. Only tiny amounts have been released with the steam (still en0ugh to be over legal limits, but nothing like the dangerous levels seen after Chernobyl exploded). Keep updated
Sources: BBC News, ABC News, MSNBC, BBC iPlayer, Hypocentral.com, usgs.gov, Telegraph
Did you watch it? I found all the inventions stunning (especially the kinetic models that were weird (and to be honest i think weird is good as being normal is boring 😛 )) and you may have seen the A.I penguins on The Gadget Show and you may have also recognised Jem from Bang Goes The Theory. But one invention i did find quite cruel to animals, the fly powered clock and robots. Now, I don’t exactly like flies but I don’t like the idea of using them as energy for electrical devices. These devices would transform the biomass energy in the fly into electrical energy, so it needs to be constantly “fed” flies. They also said that this could be a new renewable source, but I do think it is cruel, surely if you had a bigger electrical device wouldn’t you need to feed it bigger animals for enough energy to power it?? But that’s just my opinion, I don’t know what everybody else thinks.
Yep, another post on bang. this week we see why at the moment, planes cannot fly due to the volcanic ash, why it is so easy to ski, even though snow isn’t slippery and how can we reduce CO2 emissions when we are burning coal.
You may have also seen adverts about training your brain, which is all on the bang website (the link is below along with the bbc iplayer link) . The website also shows you what happens to a candle in zero G and how to turn water into ice with a single bang. You can also ask Dr Yan any unsolved questions you have got, like whats deja vu, why do onions make you cry and what is the meaning of life (although he may not be able to answer the last one, best person to ask is Matthew Bellamy :D). I am also pretty sure the 3D Doctor. Who is still there, with his new assistant called Amelia! 😀
Bang website, and i have just looked for the new bang episode on iplayer and it’s not there not sure why so I’ll keep looking 😀
Yep, another Band Goes the Theory Blog for the new episode (there wasn’t one last week as i was on holiday). This week Jem makes steel from iron and another unusual (smelly) ingredient, Dallas shows us he can’t swim and tries to improve by looking at another mammals techniques, Liz finds out if we could live forever by looking at Naked Mole Rats (not the ones off fallout 3) and Dr Yan asks us, what is similar between fizzy drinks and diesel. So heres the link to the Bang website and a link to bbc iplayer where you can catch up if you missed any episodes.
As a follow up to last weekends Wonders of the Solar System – here’s a BBC article on Saturn and its rings.
PS These links will work only until the BBC’s time limit.